1. Field of the Invention
The present invention relates to a label manufacturing method and a label manufacturing system for manufacturing a label made of a heat sensitive adhesive sheet having a heat sensitive adhesive layer formed on a single side of a sheet-like substrate, which normally exhibits no adhesive properties but develops adhesive properties when it is heated.
2. Description of the Related Art
Conventionally, the heat sensitive adhesive sheet having the heat sensitive adhesive layer that develops adhesive properties when it is heated has been commercialized. Such a heat sensitive adhesive sheet has advantages that the sheet before being heated can be handled easily because it does not have the adhesive properties and that it does not need release paper so that industrial waste is not produced. Further, this label made of the heat sensitive adhesive sheet is attached onto various articles and is used in many fields such as a display like a bar code or the like for a point of sale (POS) of products such as foods, a shipping tag for distribution and delivery, a baggage tag in a hotel or a vehicle, or a display of contents of a bottle, a can, a cartridge or the like.
In some applications, this label may be configured to have the adhesive portion and a non-adhesive portion formed side by side, and the adhesive portion and the non-adhesive portion are used as one set. For instance, displays having the same contents are formed on the adhesive portion and the non-adhesive portion, and the adhesive portion is attached onto an article while only the non-adhesive portion corresponding to the adhesive portion is cut off and is removed from the article so as to be saved as a copy. In this case, the adhesive portion that develops adhesive properties by being heated and the non-adhesive portion that is not heated and does not develop adhesive properties are mixed in one label.
Note that a thermal head that is usually used as a recording head of a thermal printer is used for heating the heat sensitive adhesive layer of the heat sensitive adhesive sheet in many cases (see Patent Documents 1 and 2). In this case, the heat sensitive adhesive layer of the heat sensitive adhesive sheet is pressed to the thermal head while the heat sensitive adhesive sheet is transported so that the entire surface or a part of the surface of the heat sensitive adhesive layer is thermally activated so as to develop adhesive strength. When the thermal head is used, it is relatively easy to dispose a heated part and a non-heated part mixedly in the heat sensitive adhesive layer. Usually, when the heat sensitive adhesive layer of the heat sensitive adhesive sheet is heated, the thermal head heats the heat sensitive adhesive layer based on a predetermined pattern. For instance, Patent Document 2 discloses to drive the thermal head by selecting any one of a plurality of pieces of control data. Since each piece of the control data includes a heating pattern (energizing pattern of each heating element of the thermal head), the thermal head operates in accordance with the heating pattern of the selected piece of control data so as to produce the adhesive portion (part in which the heat sensitive adhesive layer is thermally activated) and the non-adhesive portion (part in which the heat sensitive adhesive layer is not thermally activated) in the heat sensitive adhesive sheet.
[Patent Document 1] JP 2004-243606 A
[Patent Document 2] JP 2004-136972 A
According to the apparatus described in Patent Document 2, it is possible to dispose the adhesive portion and the non-adhesive portion mixedly in the heat sensitive adhesive sheet in accordance with any one of the plurality of pieces of control data (a plurality of heating patterns). According to this method, there are the same number of variations of label manufacturing methods as the types of heating patterns of the control data stored in advance. However, if it is required to manufacture many types of labels in small quantities, it is desired to set more various heating patterns. In that case, it is preferable to increase the number of pieces of control data stored in advance, which requires a corresponding increase in capacity of storage means. If the number of pieces of control data stored in advance is increased abruptly, many of pieces control data that will not actually be used may be stored, causing a possibility of increase in the capacity of the storage means in a meaningless way.
Further, even if a size or a shape of the label to be manufactured needs to be changed, it is impossible for a user to modify the heating pattern in a flexible manner. It is impossible to make an adhesive portion having a size or a shape that deviates from any one of the heating patterns included in the plurality of pieces of control data stored in advance. In addition, if a mechanical error (such as transport error of heat sensitive adhesive sheet) occurs in operation of the label manufacturing apparatus, it is impossible for the user to perform a fine adjustment of the heating pattern for correcting the error. In other words, the mechanical error in operation of the label manufacturing apparatus may cause the situation where an adhesive portion having a desired shape and a desired size cannot be formed, and the situation cannot be corrected.